Modern hygiene articles for acquiring body fluids, such as urine, perspiration, menstrual bleeding or secretions from wounds, are based in principle on a layered sequence of a plurality of plies of functional, flexurally yielding materials which, in appropriate form, acquire the discharged fluid from the emission site and distribute it, store it and close it off with respect to the exterior. Efforts are made additionally to minimize wetting back to the skin of the wearer, and suitable elastic elements, such as elastic closure systems and specific elastication of individual regions, are used with the aim of optimum conformity to the user's anatomy.
This procedure is encountered consistently in the development of a very wide variety of hygiene and medical articles, such as, for instance, infant nappies, sanitary towels, incontinence products, dressing materials, clinical absorption material, packaging material for foods, etc.
It is fundamentally desirable to optimize the number and quantity of the materials for fulfilling this function in order to achieve economic and environmental rationalization not only of the levels of material and energy employed in the production of these products but also of the volume of the product and hence its storage, distribution and disposal requirement.
Products with the function described above consist in principle of a first outer ply (topsheet) facing the skin of the wearer and intended to have skin-kindly qualities; an opposite, second outer ply (backsheet) intended to provide security against unwanted emergence of fluid into clothing or the surrounding area; and also, incorporated therein, an absorption core for the absorption and storage of the body fluid. This absorption core is intended to fulfill the functions of rapid fluid acquisition, rapid transverse distribution in the product, and reliable storage of the fluid in the absorption core, with the ultimate aim of minimal wetting back by the fluid acquired in the absorption core.
In the products known from the art, the function of fluid acquisition is achieved by plies of rapidly fluid-conducting materials, such as, for instance, lightweight, bulky spunbonded nonwovens or needle-punched felts based on polyester, polypropylene or polyethylene; the function of distributing the fluid in the absorption core is achieved by cellulosic fibers, cellulose or chemically modified cellulosic fibers (“Curly fibers”); and the function of fluid storage is achieved by superabsorbent polymers. It is in the nature of the matter that here, owing to the multiple effect of the individual materials, there is a partial overlap of functions. It is also obvious that materials which are able effectively to transport and conduct fluids fulfill this transport function, normally, equally in all directions. Effective transport and conduct of fluid away from the skin side in the direction of the absorption core therefore generally implies a comparably effective transport and conduct effect back in the direction of the skin side of the wearer, which promotes unwanted back-wetting.
It is therefore considered an object of the present invention to configure a hygiene article of the generic type specified at the outset in such a way that the properties of the hygiene article are improved with minimal cost and deployment of material and manufacture. Here, where possible, the storage of fluid is to be ensured very rapidly and reliably, and at the same time the risk of back-wetting is to be reduced.